Don't call require.config() in main.coffee

The default scenario is to use bokeh*.js files that contain all
dependencies which are resolved at compilation time, so additional
call to require.config() does nothing.

Another scenario is to require(["main"]) explicitly. In the case
custom require.config() will have to be called anyway to set baseUrl.
Don't use require.config() but link js/config.js
Automatically generate js/config.js
Merge pull request #295 from mattpap/requirejs_config

Fix issues with require.config()